All the personnel were driven in a convoy some 250 miles to Tunisia, under heavy military guard from the ground, the air and at sea.

The move comes amid fierce fighting between rival militias that has been growing closer to the embassy, and there was a tweet from the U.S. ambassador in Tripoli within the last 24 hours, warning of the nearing violence.

"At the request of the Department of State, the U.S. military assisted in the relocation of personnel from the U.S. Embassy in Tripoli, Libya on Saturday, July 26," Pentagon Press Secretary Rear Admiral John Kirby said today.

The mission was conducted under security from "F-16s, ISR assets and an Airborne Response Force with MV-22 Ospreys," he said. "The mission was conducted without incident, and the entire operation lasted approximately five hours."

Here are some further details of the mission, provided to ABC News by a U.S. official, about the military assistance provided to the evacuation of U.S. personnel from Tripoli:

Embassy staff were evacuated in a convoy of armored SUVs, a senior administration official tells ABC News. The official would not discuss the total number of vehicles.

Before leaving, staff destroyed documents. "Classified holdings were destroyed in accordance with procedures. Some classified equipment not normally destroyed was taken out," State Dept. spokeswoman Marie Harf told ABC.

Flying above the convoy as it headed west was at least one drone. The official believes it was a Predator, as those are the ones that fly missions over Libya.

There were two F-16 fighters that were on overwatch, which means they were in the general area if needed, not directly above the convoy.

There were two MV-22 Ospreys, each carrying a complement of Marines aboard who could serve as a quick reaction force if needed. Kirby referred to them as an "airborne response force," and the U.S. official believes it was about 40 to 50 Marines. These two aircraft were definitely kept out of the line of sight of the convoy. These Marines have been stationed at Sigonnella, in Sicily for months so they could be close to North Africa if needed.

There was a destroyer offshore in international waters that could also provide assistance if needed.

The official says there were about 150 Americans that were taken out in the convoy, with more than 80 of them being Marines. The Marines have had a beefed up presence at the embassy in Libya since last year to provide additional security.

The tick-tock times for the daylight operation aren't precise, but it took five hours to complete. The official thinks the operation began around 8 a.m. local time in Tripoli and wrapped up by 1 p.m.